Glad you like them, an interesting part of the model/Toy coin learning series, still in use at Schools today but in plastic and decimal denominations.
David Evans produced a catalogue British Cardboard Coins from 1860 (Galata) back in 2004 documenting Cardboard coins he had found and collected over many years, due mainly to the composition, and the fact children were involved, most of the earlier issues haven't stood the test of time and are now quite rare,
Partial sets dating from the 1930s up until to 1964, during which the number and types seem to peak, still turn up on fairly frequently on Ebay for a couple of pounds each, but the earliest (embossed) issues circa 1860 to the early 1900s have become increasingly difficult to find in any condition and can fetch between £10 to £15 pounds each, dependent of date/type and condition.
I am always interested should anyone have a few tucked away
John